Study On The Influence Of Residential Green Space On PM2.5 Based On ENVI-met Simulation

Nowadays,air pollution is becoming more and more serious,among which fine particulate matter PM2.5 is one of the main causes of haze in urban environment,causing great harm to human health.Residential areas are closely related to the life of urban residents.While people are committed to improving the air quality in cities,the air quality in residential areas also attracts much attention.As an important factor affecting the air quality in residential areas,green space is one of the focuses of the research in this direction.Previous research methods on air quality are mainly divided into two categories: one is field monitoring,through which data are obtained and analyzed;Second,simulation software analysis,such as CFD simulation software.Relatively,compared with the actual measurement,the simulation software can reduce the interference effect of external irrelevant factors,and can repeat the simulation of a single or multiple indicators,so more and more scholars pay attention to it.This paper takes typical residential areas in Wuhan as the research object,firstly through satellite image extraction,literature summarization and other methods,conducts sampling survey on the layout characteristics and green space characteristics of residential areas in Wuhan,and summarizes the layout form characteristics of green space.To extract the sample plot of three kinds of typical residential land as a model,with the rate,rate of trees,green space layout form,tree layout form a measure of number and form,respectively,according to the standard of residential land in urban land classification is divided into category,class ii and class iii,simulated respectively from three kinds of typical communities under different green space index,density and distribution of PM2.5in the district,the green space factor is obtained the influence of PM2.5 in their neighborhood.The selection indicators are: green land rate 20%,35%,50%;Tree rate: 10%,30%,50;Green space layout: decentralized,centralized;Tree layout: all around,uniform,concentrated.The research shows that :(1)when the green space rate is low,improving green space has a better effect on PM2.5 reduction.When the green land rate reaches 35%,the influence of green land on the overall PM2.5 concentration of the community becomes smaller and the reduction speed becomes slower.(2)Between 10%-30% of the arbor rate,increasing the arbor rate can better reduce air particulate matter and better block the diffusion of PM2.5.Under the condition of 50% arbor rate,the best blocking effect of PM2.5 diffusion is achieved,but dense arbor can also cause local PM2.5 cannot be evacuated in time.(3)In the three types of residential areas,distributed and centralized green space layout has advantages.Combining the actual situation and the regional microclimate to arrange the green space,forming the mixed green space layout form can improve the PM2.5 in the community best effect.(4)The three types of tree layout have their own advantages and disadvantages.The four-way tree layout has the greatest advantage in preventing PM2.5 from entering the community,the centralized tree has the best effect in reducing the overall concentration of PM2.5,and the uniform tree layout has the middle effect.The research results are helpful to optimize the design strategy of residential green space and enhance the ecological value of residential green space.